Silane-Functionalized Hydrocarbon Polymer Modifiers For Elastomeric Compositions

ABSTRACT

An elastomeric composition and method incorporating a hydrocarbon polymer modifier with improved permanence. The composition comprises elastomer, filler and silane-functionalized hydrocarbon polymer modifier (Si-HPM) made in a pre-reaction adapted to couple the Si-HPM to the elastomer, filler or both, wherein the Si-HPM comprises an interpolymer of monomers chosen from piperylenes, cyclic pentadienes, aromatics, limonenes, pinenes, amylenes, and combinations thereof.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation in part of U.S. applicationSer. No. 15/165,241, filed May 26, 2016. which is a divisionalapplication of U.S. application Ser. No. 13/822,103, filed May 3, 2013,which is a National Stage Application of International Application No.PCT/US2011/049139 filed Aug. 25, 2011, which claims priority to and thebenefit of U.S. Ser. No. 61/508,226, filed Jul. 15, 2011, U.S. Ser. No.61/508,238, filed Jul. 15, 2011 (corresponding to U.S. Ser. No.13/821,683, now U.S. Publication No. 2013-0220516), U.S. Ser. No.61/392,751, filed Oct. 13, 2010 (corresponding to U.S. Ser. No.13/822,651, now U.S. Pat. No. 8,653,195), and U.S. Ser. No. 61/392,765,filed Oct. 13, 2010 (corresponding to U.S. Ser. No. 13/821,715, now U.S.Pat. No. 8,735,500).

BACKGROUND (1) Field of the Invention

This invention relates to hydrocarbon polymer modifiers and their use inelastomeric compositions. More particularly, this invention relates tothe use of hydrocarbon polymer modifiers in cured elastomericcompositions.

(2) Description of Related Art Including Information Disclosed Under 37CFR 1.97-1.98

The selection of ingredients for the commercial formulation of anelastomeric composition depends upon the balance of properties desired,the application, and the end use for the particular application. Forexample, in the tire industry the balance between processing propertiesof the green (uncured) composition in the tire plant and in-serviceperformance of the cured rubber tire composite is of particularimportance. Conventional oil processing aids have been used in many tirecomponents: tread compounds often contain polybutadiene rubber (“BR”),oil-extended polybutadiene rubber (“OE-BR”), styrene-butadiene rubber(“SBR”), oil-extended styrene-butadiene rubber (“OE-SBR”),isoprene-butadiene rubber (“IBR”), and styrene-isoprene-butadiene rubber(“SIBR”); sidewall and ply coats can contain butyl rubber and SBR andhave used free aromatic oils as processing aids; internal components,such as the steel belt skim coat, gum strips, cushions, barriers, bases,and wedges, contain predominantly natural rubber and have used aromaticoils.

Generally, the raw ingredients and materials used in tire compoundingimpact all tire performance variables, thus, any new alternative toconventional processing oils must be compatible with the rubbers, notinterfere with cure, be easily dispersed in all tire compounds, be costeffective, and not adversely impact tire performance. Rollingresistance, dry and wet skid characteristics, heat buildup, and so onare important performance characteristics, as well as the ability toimprove the endurance of tires used in a wide variety of conditions,such as is required for agricultural tires, aircraft tires, earthmovertires, heavy-duty truck tires, mining tires, motorcycle tires, mediumtruck tires, and passenger car tires. On the other hand, maintainingease of processability of the uncured elastomeric composition is also ofsignificant importance. Additionally, there still remain the goals ofimproving air impermeability properties, flex fatigue properties, andthe adhesion of the elastomeric composition to adjoining tire componentswithout affecting the processability of the uncured elastomericcomposition or while maintaining or improving the physical propertyperformance of the cured elastomeric composition.

It is also known to improve tire tread performance by compoundingamorphous or semicrystalline resins in the rubber base to improve tireperformance, e.g., aliphatic resins having a high glass transitiontemperature (Tg). These materials can be miscible, which increasescompound Tg for better wet traction, have some degree of immiscibility,which broadens compound Tg in wet traction region, or be immiscible inone or all of the polymers used, which has relatively no effect on thecompound Tg. The immiscibility can be demonstrated by independent Tgpeaks for the two different phases, i.e., the Tg corresponding to therubber phase is not significantly changed by the immiscible resin. Treadcompositions based on these formulations can have a low rollingresistance at normal use temperatures and/or a high grip at hightemperature or “borderline” conditions.

Unfortunately, high concentrations of low molecular weight additives ingeneral and immiscible resins in particular can migrate to the surfaceof the tread or other tire components over time, which can dramaticallychange the rubber compound characteristics and/or tire performance. Whenthe Tg of the tire compound is increased by the addition of a miscible,high Tg additive, the wet traction improves while the treadwear androlling resistance are negatively impacted.

There is thus a need for improving the permanence of rubber compoundingadditives in general, and for improving wet traction in a tire treadwhile maintaining or improving treadwear and rolling resistance.

SUMMARY

The present invention provides in one embodiment an elastomericcomposition comprising a hydrocarbon polymer modifier (“HPM”). In anembodiment, the HPM is functionalized with at least one functionalgroup, and in another embodiment, the at least one functional groupcomprises a silane structure to provide at least onesilane-functionalized hydrocarbon polymer modifier (“Si-HPM”). TheSi-HPM is made in a pre-reaction and is anchored or anchorable via thefunctional group(s) to another component in the elastomeric composition,e.g., a filler and/or polymer depending on the nature of the functionalgroup(s), significantly improving long term elastomeric performance,e.g., in a tire or tire component. The elastomeric compositions of thepresent invention are useful in a variety of applications such aspneumatic tire components, hoses, belts, solid tires, footwearcomponents, rollers for graphic arts applications, vibration isolationdevices, pharmaceutical devices, adhesives, sealants, protectivecoatings, and bladders for fluid retention and curing purposes. In tiretread compounds, one embodiment of the present invention allows the tirecompounder to improve the wet traction with the use of a high-Tg HPMwhile maintaining or improving tread wear and rolling resistance throughimproved filler dispersion.

DETAILED DESCRIPTION

Various specific embodiments, versions, and examples are describedherein, including exemplary embodiments and definitions that are adoptedfor purposes of understanding the claimed invention. While the followingdetailed description gives specific preferred embodiments, those skilledin the art will appreciate that these embodiments are exemplary only,and that the invention can be practiced in other ways. For purposes ofdetermining infringement, the scope of the invention will refer to anyone or more of the appended claims, including their equivalents, andelements or limitations that are equivalent to those that are recited.Any reference to the “invention” may refer to one or more, but notnecessarily all, of the inventions defined by the claims.

The term “phr” means parts per hundred parts of rubber by weight, and isa measure common in the art wherein components of a composition aremeasured relative to the total of all of the elastomer (rubber)components. The total phr or parts for all rubber components, whetherone, two, three, or more different rubber components are present in agiven recipe is always defined as 100 phr. Other non-rubber componentsare generally proportional to the 100 parts of rubber and the relativeamounts may be expressed in phr. The term “olefinic hydrogen” meanshydrogen adjacent to an olefinic double bond. The term “aromatichydrogen” is based on the total moles of hydrogen in the interpolymer asdetermined by proton nuclear magnetic resonance (H-NMR).

The term “silane” means any silicon analog of a substituted orunsubstituted alkane hydrocarbon. The term “silane structure” refers toany compound, moiety or group containing a tetravalent silicon atom. Theterm “interpolymer” means any polymer or oligomer having a numberaverage molecular weight of 500 or more prepared by the polymerizationor oligomerization of at least two different monomers, includingcopolymers, terpolymers, tetrapolymers, etc. As used herein, referenceto monomers in an interpolymer is understood to refer to theas-polymerized and/or as-derivatized units derived from that monomer.The terms polymer and interpolymer are used broadly herein and in theclaims to encompass higher oligomers having a number average molecularweight (Mn) equal to or greater than 500, as well as compounds that meetthe molecular weight requirements for polymers according to classic ASTMdefinitions.

All hydrocarbon polymer modifier component percentages listed herein areweight percentages, unless otherwise noted. “Substantially free” of aparticular component in reference to a composition is defined to meanthat the particular component comprises less than 0.5 wt % in thecomposition, or more preferably less than 0.25 wt % of the component inthe composition, or most preferably less than 0.1 wt % of the componentin the composition.

The term “elastomer” as used herein refers to any polymer or combinationof polymers consistent with the ASTM D1566 definition, incorporatedherein by reference. As used herein, the term “elastomer” may be usedinterchangeably with the term “rubber.”

As used herein, “immiscibility” is present when experimental techniquesto observe the glass transition temperature (Tg) show distinct separateand independent peaks for the elastomer and the interpolymer. Misciblesystems on the other hand generally result in a single Tg peak which isshifted from the Tg peak for the elastomer alone, or which has ashoulder, due to the presence of the miscible interpolymer in theelastomer phase. Tg can be determined by differential scanningcalorimetry (“DSC”) as described herein.

The term “filler” as used herein refers to any material are used toreinforce or modify physical properties, impart certain processingproperties, or reduce cost of an elastomeric composition.

The elastomeric compositions of the invention can include variouselastomers, hydrocarbon polymer modifiers, fillers and, in someembodiments, a bifunctional organosilane crosslinking agent, which canoptionally be pre-reacted with the modifier, the filler, the elastomer,or any combination thereof.

In an embodiment, the hydrocarbon polymer modifier is functionalized,i.e., a functionalized hydrocarbon polymer modifier, with one or morefunctional groups for coupling the hydrocarbon polymer modifier to theat least one elastomer, to the at least one filler or to both the atleast one elastomer and the at least one filler. For example, where thefiller comprises silica, the functional groups can have a silanestructure, and/or the functional groups can have a structure, such asolefinic unsaturation, which is suitable for silylation to incorporate asilane structure either as a pre-reaction or dynamically duringelastomer processing, or the silane structure can be incorporated byincluding a silane-functional monomer in the interpolymerization of themodifier monomers.

As used herein, the term “pre-reaction” when referring to thefunctionalized hydrocarbon polymer modifier/interpolymer (also referredto herein as Si-HPM) means that the Si-HPM is made prior to beingcombined with other components of the elastomeric composition, such asthe elastomer or filler. The term “pre-reaction” is different from theterm “in-situ.” The term “in-situ” refers to a compounding process whereall components, such as a functional groups for coupling, thehydrocarbon polymer modifier, the at least one elastomer, and the atleast one filler, are mixed together. In such in-situ processes, incontrast to the presently claimed pre-reaction process, the hydrocarbonpolymer modifier is functionalized, if at all, after the modifier iscombined with the elastomer in the presence of coupling agents.

In an embodiment, the hydrocarbon polymer modifier can be functionalizedusing a bifunctional organosilane crosslinking agent comprising asilicon functional group and an organo-functional group. Theorgano-functional group can be used to couple one end of thecrosslinking agent to the hydrocarbon polymer modifier at a reactivebinding site, e.g., via olefinic unsaturation or incorporated duringinterpolymerization. The silicon functional groups can be used to bindthe other end of the crosslinking agent to the silica filler,effectively anchoring the hydrocarbon polymer modifier in theelastomeric matrix. The hydrocarbon polymer modifier can also be graftedto the elastomer or otherwise bound, for example, via additionalolefinically unsaturated sites in the elastomer and the modifier.

In one embodiment, the elastomeric composition is used in a tire, suchas in the tread, or other tire component. In tire construction and modeltread formulations, the elastomeric composition may comprise: 100 phr ofelastomer(s); from 50 to 90 phr of silica and optionally other fillerssuch as, for example, carbon black; from 5 to 50 phr of functionalizedhydrocarbon polymer modifier(s); optionally, about 0.5 to 3 phr of ZnO;optionally, about 1 phr of stearic acid; optionally, about 1 to 4 phr ofaccelerators; optionally, about 1 to 2 phr of sulfur; optionally, up toabout 5 phr of other processing aids; and optionally, depending on theapplication, about 0.5 to 4 phr of antidegradants.

In another embodiment, the elastomeric composition may comprise: 100 phrof elastomer(s); from 50 to 90 phr of silica and optionally otherfillers such as, for example, carbon black; from 5 to 50 phr ofhydrocarbon polymer modifier(s) comprising from 1 to 10 mole percentolefinic hydrogen, based on the total moles of hydrogen in thehydrocarbon polymer modifier; from 0.1 to 8 phr of a bifunctionalorganosilane crosslinking agent; optionally, about 0.5 to 3 phr of ZnO;optionally, about 1 phr of stearic acid; optionally, about 1 to 4 phr ofaccelerators; optionally, about 1 to 2 phr of sulfur; optionally, up toabout 5 phr of other processing aids; and optionally, depending on theapplication, about 0.5 to 4 phr of antidegradants.

In some embodiments, the hydrocarbon polymer modifier(s) can be used inaddition to other processing aids and oils, or as a replacement forother processing aids and oils. Preferably, the elastomeric compositionsare substantially free of aromatic oils. Substantially free of aromaticoils is defined to mean that the elastomeric composition comprises lessthan 0.5 phr of aromatic oil, or more preferably less than 0.25 phr ofaromatic oil, or most preferably less than 0.1 phr of aromatic oil.Aromatic oils are compounds containing at least 35% by mass of single-and multiple-ring compounds. Generally, aromatic oils containaromatically unsaturated polycyclic components.

In some embodiments, replacing aromatic oil with hydrocarbon polymermodifier(s) can improve compound tack, adhesion, and tear strength;improve aged tensile strength retention; improve abrasion resistance andstorage modulus, G′; provide an increase in tan delta at 0° C., whichcan be used as a predictor for wet tire traction; provide an increase intan delta within the range of from 30° C. to 70° C., which can be usedas an indicator of dry traction, rolling resistance and other enhancedperformance characteristics under normal use conditions; or provide anincrease in tan delta above 70° C., which can be used as an indicator oftire grip and other enhanced performance characteristics under extremeuse conditions; or any combination of any two or more or all of theseimprovements.

In some embodiments, the hydrocarbon polymer modifiers can be miscibleor immiscible in the elastomer. Immiscibility can result, for example,where the solubility parameters of the elastomer and the HPM aresufficiently different, i.e., the HPM is incompatible with theelastomer. In another embodiment, the HPM can have a sufficiently highmolecular weight to confer immiscibility in an elastomeric matrix, evenwhere the HPM would be compatible with the elastomer mix due to similarsolubility parameters and otherwise miscible if the molecular weightwere lower.

In some embodiments, the Si-HPM is co-curable or co-cured with theelastomer. The Si-HPM in one embodiment comprises olefinic unsaturation(in excess of that required for any silylation or otherfunctionalization) or other functionality that facilitates participationin the crosslinking or vulcanization of the rubber mixture. In oneembodiment, the Si-HPM is co-curable or co-cured with filler in theelastomeric composition, for example, with silica filler. Co-curing theSi-HPM, which can be either miscible or immiscible in the elastomer, canfurther inhibit migration of the Si-HPM to a surface of the cured rubberarticle, thus allowing the rubber composition to retain its desiredproperties for a longer period of time up to the useful lifetime of thearticle.

The Si-HPM in one embodiment can be manufactured in a one-step processby adding monomers to the reactor or modification of the finishing line.In another embodiment, the Si-HPM can be produced in a post-reactorprocess, e.g., a post-reactor, pre-compounding process. In oneparticular embodiment, silanes capable of reacting or interacting withthe filler and curing into the elastomer matrix are included in thecompounding formulation or process. In another embodiment, the Si-HPMcan be coupled to the filler, optionally without reacting with theelastomer or cure system. The final products present in the elastomercomposition in various embodiments can include elastomer-resin-fillercomplexes, resin-filler complexes, elastomer-resin-elastomer complexes,elastomer-filler complexes, combinations thereof, and the like.

In one embodiment, an elastomeric composition comprises at least oneelastomer, at least one filler and at least one silane-functionalizedhydrocarbon polymer modifier. The Si-HPM in an embodiment comprises aninterpolymer comprising at least one monomer chosen from piperylenes,cyclic pentadienes, aromatics, limonenes, pinenes, and amylenes, and caninclude at least one functional group to couple the Si-HPM to the atleast one filler, or to both the at least one elastomer and the at leastone filler to the at least one elastomer. In another embodiment, the HPMcomprises interpolymerized monomers selected from the group consistingof piperylenes, cyclic pentadienes, aromatics, limonenes, pinenes,amylenes, terpenes, and combinations thereof.

In one embodiment, the one or more functional groups further compriseolefinic unsaturation, wherein the functionalized interpolymer comprisesat least 1 mole percent olefinic hydrogen, based on the total moles ofhydrogen in the interpolymer. In another embodiment, the silanestructure can be provided, for example, by silylation at sites ofolefinic unsaturation in the interpolymer with a bifunctionalorganosilane compound, either before or after combining the interpolymerwith the elastomer and/or the filler.

In another embodiment, the Si-HPM comprises the reaction product of theinterpolymer and a bifunctional organosilane crosslinking agent of theformula X₃Si—R—F—[R—Si—X₃]_(p) wherein each X is independently a siliconfunctional group, each R is independently a divalent substituted orunsubstituted hydrocarbon group of from 1 to 20 carbon atoms, F is amonovalent or multivalent organo-functional group, p is 0 when F ismonovalent and p is at least 1 when F is multivalent. In one embodiment,X is hydroxy or R¹—O— wherein R¹ is an alkyl, alkoxyalkyl, aryl, aralkylor cycloalkyl group of up to 20 carbon atoms, R is alkylene, and when pis 0 F is selected from amino, amido, hydroxy, alkoxy, halo, mercapto,hydrosilyl, carboxy, acyl, vinyl, allyl, styryl, ureido, epoxy,isocyanato, glycidoxy, and acryloxy groups, and when p is 1 F isdivalent polysulfide of from 2 to 20 sulfur atoms.

In an embodiment, the at least one filler comprises silica.

In one embodiment, the interpolymer comprises: (i) at least onepiperylene component; (ii) at least one cyclic pentadiene component; and(iii) at least one aromatic component, wherein the interpolymercomprises a softening point from 40° C. to 160° C. As one example, theinterpolymer can have a softening point from 110° C. to 150° C., numberaverage molecular weight greater than 800, weight average molecularweight greater than 2500, z average molecular weight greater than 20,000and at least 5 mole percent aromatic hydrogen.

In another embodiment, the interpolymer comprises: (i) a piperylenecomponent; (ii) an aromatic component; and (iii) a cyclic pentadienecomponent comprising a dicyclopentadiene fraction (DCPD fraction) and adimethylcyclopentadiene fraction (MCPD fraction), wherein a weight ratioof the MCPD fraction to the DCPD fraction is from 0.8:1 to 100:1,wherein the MCPD fraction is at least 20 wt % of the cyclic pentadienecomponent, and wherein the interpolymer comprises: (a) Mn greater than400; (b) Mz less than 15,000; and (c) at least 8 mole percent aromatichydrogen, based on the total moles of hydrogen in the interpolymer.

In other embodiments, the interpolymer is prepared from a monomermixture comprising from 60 wt % to 90 wt % piperylene components, from 5wt % to 15 wt % cyclic components, and from 5 wt % to 20 wt % aromaticcomponents, by weight of the monomer mixture; or additionally oralternatively, the interpolymer has a weight average molecular weight offrom 520 to 650 g/mole and a Tg of from 48° C. to 53° C.

In various embodiments, the interpolymer is coupled via at least one ofthe one or more functional groups to the at least one elastomer, theinterpolymer is coupled via at least one of the one or more functionalgroups to the at least one filler, the interpolymer is coupled via atleast one of the one or more functional groups to a combination of theat least one elastomer and the at least one filler, the at least oneelastomer is coupled to the at least one filler or any combinationthereof, or the like.

In an embodiment, the interpolymer is immiscible with the at least oneelastomer. In another embodiment, the functionalized hydrocarbon polymermodifier is present at from 5 to 50 phr.

In another embodiment, a tire or tire component comprises theelastomeric composition described herein.

In a further embodiment, a method comprises: melt processing anelastomeric mixture to form an elastomeric composition in the shape ofan article, wherein the elastomeric mixture comprises: (i) at least oneelastomer; (ii) at least one hydrocarbon polymer modifier wherein thehydrocarbon polymer modifier comprises an interpolymer comprising atleast one monomer chosen from piperylenes, cyclic pentadienes,aromatics, limonenes, pinenes, and amylenes; (iii) a filler comprisingsilica; (iv) a bifunctional organosilane crosslinking agent; and curingthe elastomeric composition to form the article.

In various embodiments, the method comprises: coupling the bifunctionalorganosilane crosslinking agent to the filler and one or both of theelastomer and the interpolymer; coupling the interpolymer to theelastomer; binding the interpolymer to the filler; or a combinationthereof. In one embodiment, the method comprises coupling theinterpolymer to one or both of the elastomer and the filler, couplingthe elastomer to one or both of the interpolymer and the filler, andcoupling the filler to one or both of the interpolymer and theelastomer.

In an embodiment, the method comprises pre-reacting the interpolymer andthe bifunctional organosilane crosslinking agent. For example, thepre-reaction can comprise contacting the interpolymer and thebifunctional organosilane crosslinking agent in the presence of acatalyst, e.g., in an extruder. Alternatively or additionally, thepre-reaction comprises incorporating the bifunctional organosilanecrosslinking agent in a mixture of the monomers in a feed to apolymerization reactor. In a further embodiment, the method comprisescoupling the pre-reacted interpolymer-bifunctional organosilanecrosslinking agent to the filler.

In a further embodiment, the interpolymer comprises at least 1 molepercent olefinic hydrogen, based on the total moles of hydrogen in theinterpolymer. In one embodiment, the interpolymer is hydrogenated toreduce the extent of end vinyl groups, and in another embodiment, theinterpolymer is not hydrogenated to provide end vinyl groups forcoupling via silane or other intermediate functionalization.

In an embodiment of the method, the modifier is present in theelastomeric mixture in a form and an amount effective to lower theMooney viscosity.

In an embodiment, the method can further comprise adhering a buildcomponent to a surface of the elastomeric composition and co-curing thebuild component with the article to form a construct. In an embodiment,the construct comprises a tire and the article comprises a tire tread, atire innerliner, or a tire carcass.

In a further embodiment, a silylated hydrocarbon polymer modifiercomprises interpolymerized monomers selected from the group consistingof piperylenes, cyclic pentadienes, aromatics, limonenes, pinenes,amylenes, and combinations thereof, coupled with a bifunctionalorganosilane crosslinking agent. In an embodiment, the silylatedinterpolymer comprised pendant silane groups having the formula X₃Si—R—wherein each X is independently a silicon functional group and R is adivalent hydrocarbon group of from 1 to 20 carbon atoms. In oneembodiment, X is hydroxy or R¹—O—, wherein R¹ is an alkyl, alkoxyalkyl,aryl, aralkyl or cycloalkyl group of up to 20 carbon atoms, and R isalkylene.

In a further embodiment, a silica-coupled hydrocarbon polymer modifiercomprises an interpolymer comprising at least one monomer chosen frompiperylenes, cyclic pentadienes, aromatics, limonenes, pinenes, andamylenes, wherein the functionalized interpolymer comprises at least 1mole percent olefinic hydrogen, based on the total moles of hydrogen inthe interpolymer, bound to silica via the bifunctional organosilanecrosslinking agent. In an embodiment, the bifunctional organosilanecrosslinking agent is a silane having the formula X₃Si—R—F wherein eachX is independently hydroxy or R¹—O— wherein R¹ is an alkyl, alkoxyalkyl,aryl, aralkyl, or cycloalkyl group of up to 20 carbon atoms, R isalkylene of from 1 to 20 carbon atoms, and F is selected from amino,amido, hydroxy, alkoxy, halo, mercapto, hydrosilyl, carboxy, acyl,vinyl, allyl, styryl, ureido, epoxy, isocyanato, glycidoxy, and acryloxygroups, and combinations thereof. In another embodiment, thebifunctional organosilane crosslinking agent is a silane having theformula X₃Si—R—F—R—Si—X₃ wherein each X is independently hydroxy orR¹—O— wherein R¹ is an alkyl, alkoxyalkyl, aryl, aralkyl, or cycloalkylgroup of up to 20 carbon atoms, each R is alkylene of from 1 to 20carbon atoms, and F is divalent polysulfide of from 2 to 20 sulfuratoms. In another embodiment, the interpolymer is co-cured with anelastomer via the olefinic unsaturation in the interpolymer.

Elastomer

The elastomeric composition comprises at least one elastomer. In oneembodiment, a single one or a mixture of two or more of the variouselastomers are generally present in the elastomeric composition at 100phr with hydrocarbon polymer modifier being present at from 5 to 50 phr.

Typical elastomers that may be included in the elastomeric compositionsinclude butyl rubber, branched (“star-branched”) butyl rubber,star-branched polyisobutylene rubber, random copolymers of isobutyleneand para-methylstyrene (poly(isobutylene-co-p-methylstyrene)), randomcopolymers of isoprene, isobutylene and alkyl styrene, polybutadienerubber (“BR”), high cis-polybutadiene, polyisoprene rubber,isoprene-butadiene rubber (“IBR”), styrene-isoprene-butadiene rubber(“SIBR”), styrene-butadiene rubber (“SBR”), solution-styrene-butadienerubber (“sSBR”), emulsion-styrene-butadiene rubber, nitrile rubber,ethylene propylene rubber (“EP”), ethylene-propylene-diene rubber(“EPDM”), synthetic-polyisoprene, general purpose rubber, naturalrubber, and any halogenated versions of these elastomers and mixturesthereof. Useful elastomers can be made by any suitable means known inthe art, and the invention is not herein limited by the method ofproducing the elastomer.

The elastomer may or may not be halogenated. Preferred halogenatedelastomers may be selected from the group consisting of halogenatedbutyl rubber, bromobutyl rubber, chlorobutyl rubber, halogenatedbranched (“star-branched”) butyl rubbers, and halogenated randomcopolymers of isobutylene and para-methylstyrene. Such elastomer blendsare generally used for barrier components in tires.

In some embodiments, the elastomeric composition comprises a blend oftwo or more elastomers. Blends of elastomers may be reactor blendsand/or melt mixes. The individual elastomer components may be present invarious conventional amounts, with the total elastomer content in theelastomeric composition being expressed as 100 phr in the formulation.

Useful elastomers include isobutylene-based homopolymers or copolymers.An isobutylene based elastomer refers to an elastomer or polymercomprising at least 70 mol % repeat units from isobutylene. Thesepolymers can be described as random copolymers of a C₄ to C₇isomonoolefin derived unit, such as an isobutylene derived unit, and atleast one other polymerizable unit. The isobutylene-based elastomer mayor may not be halogenated.

The elastomer may also be a butyl-type rubber or branched butyl-typerubber, including halogenated versions of these elastomers. Usefulelastomers are unsaturated butyl rubbers such as homopolymers andcopolymers of olefins, isoolefins, and multiolefins. These and othertypes of useful butyl rubbers are well known and are described in RUBBERTECHNOLOGY, p. 209-581 (Morton, ed., Chapman & Hall 1995), THEVANDERBILT RUBBER HANDBOOK, p. 105-122 (Ohm ed., R.T. Vanderbilt Col.,Inc. 1990), and Kresge and Wang in 8 KIRK-OTHMER ENCYCLOPEDIA OFCHEMICAL TECHNOLOGY, p. 934 to 955 (John Wiley & Sons, Inc. 4th ed.1993), each of which are incorporated herein by reference. Non-limitingexamples of other useful unsaturated elastomers arepoly(isobutylene-co-isoprene), polyisoprene, polybutadiene,polyisobutylene, poly(styrene-co-butadiene), natural rubber,star-branched butyl rubber, and mixtures thereof.

In an embodiment, the elastomer may be rubber of types conventionallyused in tire rubber compounding for tire components that requirecharacteristics such as high strength and good abrasion along with lowhysteresis and high resilience. These elastomers may requireantidegradants in the mixed compound if they have poor resistance toboth heat and ozone. Examples of such rubbers include natural rubbers(“NR”), polyisoprene rubber (“IR”), poly(styrene-co-butadiene) rubber(“SBR”), polybutadiene rubber (“BR”), poly(isoprene-co-butadiene) rubber(“IBR”), styrene-isoprene-butadiene rubber (“SIBR”), and mixturesthereof.

The elastomeric composition may also comprise rubbers of ethylene andpropylene derived units such as ethylene-propylene rubber (“EP”) andethylene-propylene-diene rubber (“EPDM”), and their mixtures. EP andEPDM are may also be considered to be general purpose elastomers.Examples of suitable termonomers in making EPDM are ethylidenenorbornene, 1,4-hexadiene, dicyclopentadiene, as well as others.

In one embodiment, the elastomer may include a polybutadiene (BR)rubber. The Mooney viscosity of the polybutadiene rubber as measured at100° C. (ML 1+4, ASTM D1646) may range from 35 to 70, or from 40 toabout 65, or, in another embodiment, from 45 to 60.

Another useful synthetic rubber is high cis-polybutadiene (“cis-BR”). By“cis-polybutadiene” or “high cis-polybutadiene”, it is meant that1,4-cis polybutadiene is used, wherein the amount of the cis componentis at least 95%.

The elastomeric composition may also comprise a polyisoprene (IR)rubber. The Mooney viscosity of the polyisoprene rubber as measured at100° C. (ML 1+4, ASTM D1646) may range from 35 to 70, or from 40 toabout 65, or in another embodiment, from 45 to 60.

In another embodiment, the elastomer may also comprise a natural rubber.Natural rubbers are described in detail by Subramaniam in RUBBERTECHNOLOGY, p. 179-208 (Morton, ed., Chapman & Hall, 1995), hereinincorporated by reference. Desirable embodiments of the natural rubbersmay be selected from technically specified rubbers (“TSR”), such asMalaysian rubbers which include, but are not limited to, SMR CV, SMR 5,SMR 10, SMR 20, SMR 50, and mixtures thereof. Preferred natural rubbershave a Mooney viscosity at 100° C. (ML 1+4, ASTM D1646) of from 30 to120, or more preferably from 40 to 80.

In another embodiment, the elastomer may comprise a styrene rubber suchas styrene butadiene rubber (“SBR”) such as emulsion-SBR (“E-SBR”),solution SBR (S-SBR), high styrene rubber (“HSR”), and the like.Desirable embodiments of the SBRs may have a styrene content from 10 wt% to 60 wt %, such as E-SBR elastomers available from JSR Corporation,which include JSR 1500 (25 wt % styrene), JSR 1502 (25 wt % styrene),JSR 1503 (25 wt % styrene), JSR 1507 (25 wt % styrene), JSR 0202 (45 wt% styrene), JSR SL552 (25 wt % styrene), JSR SL574 (15 wt % styrene),JSR SL563 (20 wt % styrene), JSR 0051, JSR 0061, or the like. PreferredSBRs have a Mooney viscosity at 100° C. (ML 1+4, ASTM D1646) of from 30to 120, or more preferably from 40 to 80.

Other useful elastomers, including functionalized elastomers, aredescribed in U.S. Pat. No. 7,294,644, which is hereby incorporatedherein by reference in its entirety for all jurisdicitions wherepermitted. The elastomers useful in the invention can be blended withvarious other rubbers or plastics, in particular thermoplastic resinssuch as nylons or polyolefins such as polypropylene or copolymers ofpolypropylene. These compositions are useful in air barriers such asbladders, tire inner tubes, tire innerliners, air sleeves (such as inair shocks), diaphragms, as well as other applications where high air oroxygen retention is desirable.

Silane-Functionalized Hydrocarbon Polymer Modifiers (“Si-HPM”)

The elastomeric composition further comprises a hydrocarbon polymermodifier (“HPM”), including a silane-functionalized HPM (“Si-HPM”). HPMsuseful in this invention include, but are not limited to, aliphatichydrocarbon resins, aromatic modified aliphatic hydrocarbon resins,hydrogenated polycyclopentadiene resins, polycyclopentadiene resins, gumrosins, gum rosin esters, wood rosins, wood rosin esters, tall oilrosins, tall oil rosin esters, polyterpenes, aromatic modifiedpolyterpenes, terpene phenolics, aromatic modified hydrogenatedpolycyclopentadiene resins, hydrogenated aliphatic resin, hydrogenatedaliphatic aromatic resins, hydrogenated terpenes and modified terpenes,and hydrogenated rosin esters. In some embodiments, the HPM ishydrogenated. In other embodiments, the HPM is non-polar. As usedherein, non-polar means that the HPM is substantially free of monomershaving polar groups.

As used herein, reference to monomers in the HPM and/or Si-HPMinterpolymer is understood to refer to the as-polymerized and/oras-derivatized units derived from that monomer. The terms polymer andinterpolymer are used broadly herein and in the claims to encompasshigher oligomers having a number average molecular weight (Mn) equal toor greater than 500, as well as compounds that meet the molecular weightrequirements for polymers according to classic ASTM definitions.

HPMs and/or Si-HPMs can be used as elastomer compounding materials.Depending on how the HPM and/or Si-HPM is compounded, optimization ofrubber characteristics for rubber and tire durability, traction, andabrasion resistance can be achieved. The macrostructure (molecularweight, molecular weight distribution, and branching) of the HPM and/orSi-HPM provides unique properties to the polymer additive.

Suitable HPMs may include both aromatic and nonaromatic components.Differences in the HPMs are largely due to the olefins in the feedstockfrom which the hydrocarbon components are derived. The HPM may contain“aliphatic” hydrocarbon components which have a hydrocarbon chain formedfrom C₄-C₆ fractions containing variable quantities of piperylene,isoprene, mono-olefins, and non-polymerizable paraffinic compounds. SuchHPMs are based on pentene, butene, isoprene, piperylene, and containreduced quantities of cyclopentadiene or dicyclopentadiene.

The HPM may also contain “aromatic” hydrocarbon structures havingpolymeric chains which are formed of aromatic units, such as styrene,xylene, a-methylstyrene, vinyl toluene, and indene. In one embodiment,the HPM may contain an aromatic content to match the aromatic content ofthe elastomer component(s), e.g., a high aromatic content in styrenerubbers, or a low aromatic content in natural rubbers, for compatibilityor miscibility. Compatibility is desired, for example, where the HPM isused to change or shift the Tg of the elastomer domain, where improveddispersion of the HPM is desired, and/or where compatibility facilitatesinhibition of HPM migration in the elastomeric composition.Compatibility may also be desired where the HPM, Si-HPM or Si-HPMderivative is otherwise immiscible with the elastomer component(s) foranother reason, such as, for example, a high molecular weight Si-HPM,coupling of the Si-HPM to the filler, or the presence of HPM-derivedunits such as an HPM-elastomer-co-graft which limits the mobility of thebound HPM and/or facilitates dispersion of the coupled filler particles.

In another embodiment, the HPM may contain an aromatic content to impartincompatibility or immiscibility with the elastomer component(s), e.g.,a low aromatic content in styrene rubbers, or a high aromatic content innatural rubbers. Incompatibility may be beneficial where, for example,the HPM is not required or desired to shift or change the Tg of theelastomer phase, especially where the mobility of the HPM may beinhibited by high molecular weight, coupling to the filler(s), co-curingwith the elastomer component(s), or any combination thereof.

In accordance with the present invention, the Si-HPM used in rubbercompounding includes olefins such as one or more of piperylene,isoprene, amylenes, and cyclic components. The Si-HPM may also containaromatic olefins such as styrenic components and indenic components.

The functionalized hydrocarbon polymer modifier in embodiments ispreferably made from a monomer mixture comprising from 1 to 60%piperylene components, from 5 to 50% cyclic components, and from 1 to60% aromatic, preferably styrenic components. Alternatively oradditionally, in an embodiment, the Si-HPM comprises an interpolymer offrom 10 to 80 wt % units derived from at least one piperylene component,from 15 to 50 wt % units derived from at least one cyclic pentadienecomponent, and from 10 to 30 wt % units derived from at least onestyrenic component. The monomer mixture or the interpolymer mayoptionally comprise up to 5% isoprene, up to 10% amylene components, upto 5% indenic components, or any combination thereof.

Piperylene components are generally a distillate cut or syntheticmixture of C₅ diolefins, which include, but are not limited to,cis-1,3-pentadiene, trans-1,3-pentadiene, and mixed 1,3-pentadiene. Forexample, the piperylene component in one embodiment can includetrans-pentadiene-1,3, cyclopentene, cis-pentadiene, and mixturesthereof. In general, piperylene components do not include branched C₅diolefins such as isoprene. In one embodiment, the Si-HPM is preparedfrom a monomer mix having from 0.1 to 90% piperylene components, or witha range of piperylene components from any lower limit selected from 0.1,1, 10, 20, 25, 30, 35, 40, 45, or 50% piperylene components up to anyhigher upper limit selected from 80, 75, 70, 65, 60, 55, 50, 45, 40, or35% piperylene components, by weight of the total monomers in themonomer mixture. In a particularly preferred embodiment, the HPM isprepared from a monomer mix comprising from 40 to 80% piperylenecomponents, or from 40 to 65% piperylene components, or from 40 to 50%piperylene components.

In one embodiment, the Si-HPM is substantially free of isoprene. Inanother embodiment, the Si-HPM is prepared from a monomer mix thatcontains up to 15% isoprene, or less than 10% isoprene, by weight of themonomers in the mix. In yet another embodiment, the monomer mix containsless than 5% isoprene by weight of the monomers in the mix.

In general, the amylene component acts as a chain transfer agent toinhibit molecular weight growth. In an embodiment, the amylene componentis selected from the group consisting of 2-methylbutene-1,2-methylbutene-2, pentene-1, cis-pentene-2, trans-pentene-2 and mixturesthereof. In one embodiment, the Si-HPM is substantially free of amylenederived units. In another embodiment, the Si-HPM monomer mix contains upto 40% amylene, or less than 30% amylene, or less than 25% amylene, orless than 20% amylene or less than 15% amylene or less than 10% amyleneor less than 5% amylene, by weight of the monomers in the monomer mix.In yet another embodiment, the Si-HPM is prepared from a monomer mix offrom 0.1 up to 10% amylene, by weight of the monomers in the mixture.

Cyclic components are generally a distillate cut or synthetic mixture ofC₅ and C₆ cyclic olefins, diolefins, and dimers, codimers and trimers,etc. from a distillate cut. Cyclics include, but are not limited to,cyclopentene, cyclopentadiene, dicyclopentadiene, cyclohexene,1,3-cycylohexadiene, and 1,4-cyclohexadiene. A preferred cyclic iscyclopentadiene. The dicyclopentadiene may be in either the endo or exoform. The cyclics may or may not be substituted. Preferred substitutedcyclics include cyclopentadienes and dicyclopentadienes substituted witha C₁ to C₄₀ linear, branched, or cyclic alkyl group, preferably one ormore methyl groups. In one embodiment, the cyclic components areselected from the group consisting of: cyclopentadiene, cyclopentadienedimer, cyclopentadiene trimer, cyclopentadiene-C₅ codimer,cyclopentadiene-piperylene codimer, cyclopentadiene-C₄ codimer,cyclopentadiene-methyl cyclopentadiene codimer, methyl cyclopentadiene,methyl cyclopentadiene dimer, and mixtures thereof.

In general, the cyclic components increase the softening point. On theother hand, aromatics such as styrene tend to reduce the softeningpoint, but the softening point decrease can be offset by increasing therelative proportion of cyclic component(s). In one embodiment, theSi-HPM may be prepared from a monomer mix that can include up to 60%cyclics or up to 50% cyclics, by weight of the monomers in the mix.Typical lower limits include at least about 0.1% or at least about 0.5%or from about 1.0% cyclics in the monomer mix. In at least oneembodiment, the Si-HPM monomer mix may include more than 10% cycliccomponents up to 20% cyclics or more, or preferably up to 30% cyclics ormore, or more preferably up to 40% cyclics or more, or more preferablyup to 45% or 50% cyclics or more, by weight of the monomers in themonomer mixture from which the Si-HPM is prepared. In a particularlypreferred embodiment, the Si-HPM monomer mixture comprises from about 10to about 50% cyclics, or from about 20% to about 45% cyclics, or fromabout 20% to about 40% cyclic components.

Preferred aromatics that may be in the Si-HPM include one or more ofstyrene, indene, derivatives of styrene, and derivatives of indene.Particularly preferred aromatic olefins include styrene,alpha-methylstyrene, beta-methylstyrene, indene, and methylindenes, andvinyl toluenes. In general, styrenic components do not includefused-rings, such as indenics. Styrenic components include styrene,derivatives of styrene, and substituted sytrenes. In one embodiment, thearomatic component is a styrenic component that is selected from thegroup consisting of styrene, ortho-methyl-styrene, meta-methyl-styrene,para-methyl-styrene, a-methyl-styrene, t-beta-methyl-styrene, indene,methyl indene, vinyl toluene, and mixtures thereof. The aromatic orstyrenic olefins in an embodiment are present in the Si-HPM up to 60%styrenic components or up to 50%, typically from 5% to 45%, or morepreferably from 5% to 30%. In particularly preferred embodiments, theSi-HPM comprises from 10% to 25% aromatic or especially styrenicolefins.

The Si-HPM may comprise less than 15% indenic components, or less than10% indenic components. Indenic components include indene andderivatives of indene. In one embodiment, the Si-HPM comprises less than5% indenic components. In another embodiment, the Si-HPM issubstantially free of indenic components.

In one embodiment, the Si-HPM can have a weight ratio of units derivedfrom aromatic components to units derived from cyclic components, orpreferably of styrenic components to cyclic components, of from 1:2 to3:1, preferably from 1:2 to 2.5:1, or more preferably from 0.8:1 to2.2:1, or from about 1:1 to about 2:1.

In another embodiment, the Si-HPM can comprise from at least 1 molepercent aromatic hydrogen, based on the total moles of hydrogen in theinterpolymer as determined by proton nuclear magnetic resonance (H-NMR).In another embodiment the Si-HPM comprises at least 5 mol % aromatichydrogen, e.g., from 5 mol % to 30 mol % aromatic hydrogen, orpreferably from 5 mol % to 25 mol % aromatic hydrogen, or morepreferably from 5 mol % to 20 mol % aromatic hydrogen, or morepreferably from 8 mol % to 15 mol % aromatic hydrogen. In anotherembodiment, the Si-HPM comprises from 1 mol % to 20 mol % aromatichydrogen, or preferably from 2 mol % to 15 mol % aromatic hydrogen, ormore preferably from 2 mol % to 10 mol % aromatic hydrogen.

In one embodiment, there is only one interpolymer in the hydrocarbonpolymer modifier. In another embodiment, two or more interpolymers maybe blended. When two or more interpolymers are used, either at least oneof the interpolymers, or the resulting blended hydrocarbon polymermodifier, preferably both, may preferably comprise from 10 wt % to 80 wt% units derived from at least one piperylene component, from 15 wt % to50 wt % units derived from at least one cyclic pentadiene component, andfrom 10 wt % to 30 wt % units derived from at least one aromatic,preferably styrenic components. The hydrocarbon polymer modifier blendmay optionally comprise up to 5% isoprene, up to 10% amylene, and up to5% indenic components. Preferably, the elastomeric composition comprisesfrom 5 to 50 phr of hydrocarbon polymer modifier or hydrocarbon polymermodifier blend.

In another embodiment, the hydrocarbon polymer modifier is aninterpolymer of (i) a piperylene component; (ii) an aromatic component;and (iii) a cyclic pentadiene component. The cyclic pentadiene componentcomprises a dicyclopentadiene fraction (DCPD fraction) and adimethylcyclopentadiene fraction (MCPD fraction), wherein the DCPDfraction consists of any cyclopentadiene dimers and/or cyclopentadienecodimers other than CPD-MCPD, and wherein the MCPD fraction consists ofany methylcyclopentadiene dimers and/or methylcyclopentadiene codimers,including any CPD-MCPD codimers. Methylcyclopentadiene codimers includecodimers of methylcyclopentadiene with cyclopentadiene, piperylene,butadiene, and so on. Cyclopentadiene codimers include codimers ofcyclopentadiene with piperylene, butadiene, and so on. In an embodiment,the DCPD fraction comprises at least 50 wt % of dicyclopentadiene andless than 50 wt % CPD codimers. A weight ratio of the MCPD fraction tothe DCPD fraction is preferably from 0.8 to 20, more preferably 1 to 10,and the MCPD fraction is at least 20 wt % of the cyclic pentadienecomponent. When the proportion of the MCPD fraction exceeds about 0.8 or1.0 times the proportion of the DCPD fraction in the cyclic component,the interpolymer can unexpectedly have a balance of softening point,molecular weights, molecular weight distribution and aromaticity, forexample, a softening point from 40° C. to 160° C., Mn greater than 400,Mw/Mn from 1.5 to 4, Mz less than 15,000, and at least 8 mol % aromatichydrogen, based on the total moles of hydrogen in the interpolymer, orpreferably, a softening point of at least 80° C., Mn greater than 800,Mw/Mn less than 3, Mz less than 12,000 and/or at least 10 mol % aromatichydrogen. Mn is herein defined as the number-average molecular weight,Mw is herein defined as the weight-average molecular weight, and Mzherein defined as the z-average molecular weight.

The hydrocarbon polymer modifier in embodiments is preferably made froma monomer mixture comprising from 15% to 70% piperylene components, from5% to 70% cyclic components, and from 10% to 30% aromatic, preferablystyrenic components. Alternatively or additionally, in an embodiment,the hydrocarbon polymer modifier comprises an interpolymer of from 30%to 60% units derived from at least one piperylene component, from 10% to50% units derived from at least one cyclic pentadiene component, andfrom 10% to 25% units derived from at least one styrenic component. Themonomer mixture or the interpolymer may optionally comprise up to 5%isoprene, up to 10% amylene components, up to 5% indenic components, orany combination thereof.

Generally, HPMs in one embodiment have a number average molecular weight(Mn) greater than about 600 g/mole, or greater than about 800 g/mole, orgreater than about 900, or greater than about 1000 g/mole. In anembodiment, the HPM has a Mn between about 900 and 3000 g/mole, orbetween about 1000 and 1500 g/mole. In at least one embodiment, HPMshave a weight average molecular weight (Mw) greater than about 2500g/mole, or greater than about 5000 g/mole, or from about 2500 to about25,000 g/mole, or from 3000 to 20,000 g/mole. Preferably, HPMs have aweight average molecular weight of from 3500 to 15,000 g/mole, or morepreferably from about 5000 to about 10,000 g/mole. The HPM may have az-average molecular weight (Mz) greater than about 10,000 g/mole, orgreater than about 20,000 g/mole, or greater than about 30,000 g/mole.In other embodiments, Mz ranges from 10,000 to 150,000 g/mole, or from20,000 to 100,000 g/mole, or from 25,000 to 75,000 g/mole, or from30,000 to 60,000 g/mole. Mw, Mn, and Mz may be determined by gelpermeation chromatography (GPC) by the test method described herein. Themolecular weight can be measured using Tosoh EcoSEC HLC-8320GPCinstrument with enclosed Refractive Index (RI) Ultraviolet and (UV)detectors. The instrument is controlled and molecular weight iscalculated using EcoSEC Workstation (Version 1.11) software. 4 columns(PLgel 5 μm 500 Ä; 5 μm 500 Ä; 5 μm 10E3 Ä; 5 μm Mixed-D) are connectedin series for effective separation. A sample is prepared by dissolving24 mg (+/−1 mg) of hydrocarbon resin in 9 mL of tetrahydrofuran (THF)solution. The sulfur/THF solution (having a ratio of 1 mL sulfursolution per 100 mL THF solvent) is used as flow marker, for measurementof molecular weight. The dissolved sample is filtered using 0.45 mmsyringe filter. The GPC calibration is done using a series of selectedpolystyrene standards that are of narrow molecular weights and cover themolecular weight range of the columns respective range of separation.

In one embodiment, the Si-HPM has a polydispersion index (“PDI”,PDI=Mw/Mn) of 4 or less. In a particularly preferred embodiment, the HPMhas a PDI of at least about 2.5, or at least about 3, or at least about4, or at least about 5. In other embodiments, Mz/Mn is greater than 5,greater than 10, greater than 12, greater than 15, greater than 20,greater than 25, or greater than 30. In other embodiments, Mz/Mn rangesup to 150 or more, up to 100, up to 80, or up to 60. In otherembodiments, Mz/Mn is from 5 to 100, or from 10 to 80, or from 10 to 60,or from 10 to 40, or from 10 to 30, or from 15 to 40, or from 30 to 60or from 35 to 60.

In an embodiment, the HPM can have a softening point of 80° C. to 160°C., or preferably 100° C. to 160° C., or more preferably from 110° C. to150° C. Softening point can be determined according to the Ring & BallMethod, as measured by ASTM E-28.

In an embodiment, the HPM can have a glass transition temperature (Tg)of from about 30° C. to about 110° C., or from about 50° C. to 110° C.,or from about 60° C. to 100° C. Differential scanning calorimetry (DSC)may be used to determine the Tg of the HPM as described previouslyherein.

The resins described above may be produced by methods generally known inthe art for the production of HPMs, and the invention is not limited bythe method of forming the Si-HPM. Preferably, the Si-HPM is produced bycombining the olefin feed stream in a polymerization reactor with aFriedel-Crafts or Lewis Acid catalyst at a temperature between 0° C. and200° C. Friedel-Crafts polymerization is generally accomplished by useof known catalysts in a polymerization solvent, and the solvent andcatalyst may be removed by washing and distillation. The polymerizationprocess utilized for this invention may be batchwise or continuous mode.Continuous polymerization may be accomplished in a single stage or inmultiple stages.

In an embodiment, the Si-HPM comprises a functional group comprising atleast a silane structure, and may optionally comprise one or moreadditional functional groups such as olefinic unsaturation, benzylichalogen, or the like, by which the Si-HPM can be coupled to the filler,the elastomer or otherwise anchored in the elastomeric matrix. As usedherein, reference to functional groups in the Si-HPM interpolymer isunderstood to refer to the derivatized or as-coupled units derived fromthat functional group, e.g., one functional group derived from anotheror the derived form resulting from coupling directly or indirectly tothe filler, e.g., via a bifunctional crosslinking agent, or to theelastomer, e.g., via co-curing at olefinic unsaturation sites. In aparticular embodiment, the Si-HPM comprises olefinic unsaturation, e.g.,at least 1 mol % olefinic hydrogen, based on the total moles of hydrogenin the interpolymer as determined by H-NMR. Olefinic unsaturationgenerally results from the interpolymerization of diolefinic monomerssuch as piperylenes, dicyclopentadienes, etc. Olefinic unsaturation isbeneficial to facilitate crosslinking with the elastomer component(s),functionalization for co-curing with the filler, for example, orcombinations thereof, or the like.

In one embodiment, the HPM and Si-HPM are not hydrogenated (to retainthe olefin unsaturation, especially terminal vinyl groups). In anotherembodiment, the HPM and/or Si-HPM may be partially hydrogenated(especially to remove terminal vinyl groups, where desired). Thehydrogenation of the HPM and/or Si-HPM may be carried out by any methodknown in the art, and the invention is not limited by the method ofhydrogenation. For example, the hydrogenation of the HPM and/or Si-HPMmay be either a batchwise or a continuous process, e.g., catalyticallyhydrogenated. Catalysts employed for the hydrogenation of HPMs aretypically supported monometallic and bimetallic catalyst systems basedon elements from Group 6, 8, 9, 10, or 11 of the Periodic Table ofElements.

In one embodiment, the HPM and/or Si-HPM are at least partiallyhydrogenated or may be substantially hydrogenated. As used herein, atleast partially hydrogenated means that the material contains less than90% olefinic protons, more preferably less than 75% olefinic protons,more preferably less than 50% olefinic protons, more preferably lessthan 40% olefinic protons, more preferably less than 25% olefinicprotons, more preferably less than 15% olefinic protons, more preferablyless than 10% olefinic protons, more preferably less than 9% olefinicprotons, more preferably less than 8% olefinic protons, more preferablyless than 7% olefinic protons, and more preferably less than 6% olefinicprotons. As used herein, substantially hydrogenated means that thematerial contains less than 5% olefinic protons, more preferably lessthan 4% olefinic protons, more preferably less than 3% olefinic protons,more preferably less than 2% olefinic protons, more preferably less than1% olefinic protons, more preferably less than 0.5% olefinic protons,more preferably less than 0.1% olefinic protons, and more preferablyless than 0.05% olefinic protons after hydrogenation (and beforereaction with the graft monomer).

The degree of hydrogenation, when employed, is typically conducted so asto minimize and preferably avoid hydrogenation of the aromatic bonds. Inembodiments wherein the HPM and/or Si-HPM are substantiallyhydrogenated, it is believed that the graft monomer is appended to theresin/oligomer backbone as opposed to forming a copolymer (ofresin/oligomers and graft monomers) because of the lack of terminalolefinic bonds on the substantially hydrogenated HPM and/or Si-HPM (asindicated by the preferred low olefinic proton measurements).

In other embodiments, where the HPM and/or Si-HPM are not hydrogenatedor only partially hydrogenated, the presence of terminal olefinic bondsfacilitates terminal silylation, terminal organosilane coupling agentfunctionalization and/or terminal crosslinking, which may improveHPM-elastomer compatibilization and better retention of propertiesmodified by the hydrocarbon polymer modifier.

In one embodiment, the Si-HPM comprises a silane structure as thefunctional group, e.g., a pendant —SiX₃ group where X is independently asilicon functional group such as hydroxy, alkoxy, alkoxyalkoxy, aryloxy,aralkoxy or cycloalkoxy group of up to 20 carbon atoms. The siliconfunctional group X can further optionally be substituted with or coupledto a silicate, e.g., at the surface of a silica filler particle. Thesilane structure can be provided by including a silane monomer in thepolymer mix of the interpolymerization to obtain the silicon functionalSi-HPM directly, by silylating the HPM with an organo-functional silanecompound, or by dynamically functionalizing the HPM in the elastomericcomposition with a bifunctional organosilane crosslinking agent, or thelike.

As examples of silicon functional monomers that can be incorporated inthe HPM interpolymerization, there may be mentionedvinyltriethoxysilane, (cyclopentadienylpropyl)triethoxysilane and1,2-epoxypropoxypropyl)methyldiethoxysilane, either via cationicreaction (all three examples) or Diels-Alder reaction (first twoexamples).

In one embodiment, one or more silane coupling agents are used to treatthe HPM or a functionalized HPM (functionalized with a functional groupother than a silicon functional group, e.g., an organofunctional groupthat is reactive with an organofunctional group of a bifunctional silanecoupling agent) to provide silicon functionality, either as apre-reaction or dynamically in the elastomeric compositions. Suchcoupling agents are particularly desirable when silica is the primaryfiller, or is present in combination with another filler, as they helpbind the silica to the Si-HPM, and can also help bind the silica to theelastomer. The coupling agent may be a bifunctional organosilanecrosslinking agent. An “organosilane crosslinking agent” is any silanecoupled filler and/or crosslinking activator and/or silane reinforcingagent known to those skilled in the art including, but not limited to,vinyl triethoxysilane, vinyl-tris-(beta-methoxyethoxy)silane,methacryloylpropyltrimethoxysilane, gamma-amino-propyl triethoxysilane,gamma-mercaptopropyltrimethoxysilane, and the like, and mixturesthereof. In various embodiments, depending on the manner in which theyare incorporated, sulfide-type, mercapto-type, vinyl-type, amino-type,glycidoxy-type, nitro-type and chloro-type silane coupling agents may beused, alone or in any combination. Examples of silane coupling agentsinclude silane esters, amino silanes, amido silanes, ureido silanes,halo silanes, epoxy silanes, vinyl silanes, methacryloxy silanes,mercapto silanes, and isocyanato silanes.

In one embodiment, the bifunctional organosilane crosslinking agent hasthe formula:

X₃Si—R—F—[R—Si—X₃]_(p)

wherein each X is independently a silicon functional group, each R isindependently a divalent substituted or unsubstituted hydrocarbon groupof from 1 to 20 carbon atoms, preferably up to 10 carbon atoms, andespecially from 1 to 5 carbon atoms; F is a monovalent or multivalentorgano-functional group; p is 0 when F is monovalent and p is at least1, e.g., from 1 to 5, when F is multivalent. In an embodiment, X ishydroxy or R¹—O— wherein R¹ is an alkyl, alkoxyalkyl, aryl, aralkyl orcycloalkyl group of up to 20 carbon atoms, preferably up to 10 carbonatoms, and especially from 1 to 5 carbon atoms, R is alkylene preferablyup to 10 carbon atoms, and especially from 1 to 5 carbon atoms, whereinp is 0 or 1; and when p is 0 F is selected from amino, amido, hydroxy,alkoxy, halo, mercapto, carboxy, acyl, vinyl, allyl, styryl, ureido,epoxy, isocyanato, glycidoxy, and acryloxy groups; and when p is 1 F isdivalent polysulfide of from 2 to 20 sulfur atoms.

Examples of vinyl-type silane coupling agents are vinyl triethoxysilaneand vinyl trimethoxysilane.

Examples of amino-type silane coupling agents are3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane,3-(2-aminoethyl)aminopropyltriethoxysilane and 3-(2-aminoethyl)aminopropyltrimethoxysilane.

Examples of glycidoxy-type silane coupling agents areγ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane,γ-glycidoxypropylmethyldiethoxysilane andγ-glycidoxypropylmethyldimethoxysilane.

Examples of nitro-type silane coupling agents are3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane.

Examples of chloro-type silane coupling agents are3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane,2-chloroethyltrimethoxysilane and 2-chloroethyltriethoxysilane.

Specific examples of sulfide-type silane coupling agents arebis(3-triethoxysilylpropyl)tetrasulfide,bis(2-triethoxysilylethyl)tetrasulfide,bis(3-trimethoxysilylpropyl)tetrasulfide,bis(2-trimethoxysilylethyl)tetrasulfide,bis(3-triethoxysilylpropyl)trisulfide,bis(3-trimethoxysilylpropyl)trisulfide,bis(3-triethoxysilylpropyl)disulfide,bis(3-trimethoxysilylpropyl)disulfide,3-trimethoxysilylpropyl-N,N-dimethylthio carbamoyltetrasulfide,3-triethoxysilylpropyl-N,N-dimethylthio carbamoyltetrasulfide,2-triethoxysilylethyl-N,N-dimethylthio carbamoyltetrasulfide,2-trimethoxysilylethyl-N,N-dimethylthio carbamoyltetrasulfide,3-trimethoxysilylpropylbenzothiazolyl tetrasulfide,3-triethoxysilylpropylbenzothiazole tetrasulfide,3-triethoxysilylpropylmethacrylate monosulfide and3-trimethoxysilylpropylmethacrylate monosulfide. In an embodiment, thesilane coupling agent may have the general formula(C_(n)H_(2n+1)O)₃Si—(CH₂)_(m)—S_(p)—(CH₂)_(m)—Si(C_(n)H_(2n+1)O)₃wherein n represents an integer of 1 to 3, m represents an integer of 1to 9, p represents an average number of sulfur atoms and a positivenumber of more than 2.

Examples of mercapto-type silane coupling agents are3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane,2-mercaptoethyltrimethoxysilane and 2-mercaptoethyltriethoxysilane.

These silane coupling agents can be used alone or two or more kinds canbe used together.

Preferred examples of silane coupling agents in one embodiment caninclude: N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,3-methacryloxypropyltrimethoxysilane,3-(2-(vinylbenzylamino)ethylamino)-propyltrimethoxysilane,3-glycidoxypropyltrimethoxysilane, triacetoxyvinylsilane,tris-(2-methoxyethoxy)-vinylsilane, 3-chloropropyltrimethoxysilane,1-trimethoxysilyl-2-(p,m-chloromethyl)phenylethane,3-chloropropyltriethoxysilane,N-(aminoethylaminomethyl)phenyltrimethoxysilane,N-(2-aminoethyl)-3-aminopropyl tris(2-ethylhexoxy)silane,3-aminopropyltrimethoxysilane, trimethoxysilylpropylenetriamine,β(3,4-epoxycyclohexyl)ethyltrimethoxysilane,3-mercaptopropyltrimethoxysilane, 3-mercaptotriethoxysilane,3-mercaptopropylmethyldimethoxysilane,bis(2-hydroxyethyl)-3-aminopropyltrimethoxysilane,1,3-divinyltetramethyldisilazane, vinyltrimethoxysilane,2-(diphenylphosphino)ethyltriethoxysilane,2-methacryloxyethyldimethyl[3-trimethoxysilylpropyl]ammonium chloride,3-isocyanatopropyldimethylethoxysilane,N-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane, vinyltris(t-butylperoxy)silane, methyltrimethoxysilane,ethyltrimethoxysilane, phenyltrimethoxysilane, phenyltriacetoxysilane,methyltrimethoxysilane, phenyltrimethoxysilane.

The more preferred silane coupling agents are those which arecommercially available and which are recognized by those skilled in theart as being effective coupling agents. A number of organofunctionalsilanes are available, for example, from Union Carbide, SpecialtyChemicals Division, Danbury, Conn. Examples of useful silane couplingagents available from Union Carbide are disclosed in EP 0 926 265 A1,which is hereby incorporated herein by reference.

In one embodiment, the silane coupling agent is a ureido silanerepresented by the formula B_((4-n))—Si-(A-N(H)—C(O)—NH₂)_(n) wherein Ais an alkylene group containing from 1 to about 8 carbon atoms, B is ahydroxy or alkoxy group containing from 1 to about 8 carbon atoms and nis an integer from 1 to 3 provided that if n is 1 or 2, each B may bethe same or different. In one embodiment, each B is an alkoxy groupcontaining 1 to about 5 carbon atoms, particularly methyloxy or ethyloxygroups, and A is a divalent hydrocarbon group containing from 1 to 5carbon atoms. Examples of such divalent hydrocarbon groups includemethylene, ethylene, propylene, butylene, etc. Specific examples of suchureido silanes include β-ureidoethyl-trimethoxysilane;β-ureidoethyl-triethoxysilane; γ-ureidoethyl-trimethoxysilane;γ-ureidopropyl-triethoxysilane, etc.

In one embodiment, an HPM with or without olefinic unsaturation, e.g.,piperylene, C5/C9, dicyclopentadiene limonene and pinene basedinterpolymers, is treated with the bifunctional organosilanecrosslinking agent and a peroxide initiator. The peroxide initiatorforms a free radical on the HPM which reacts with the organofunctionalgroups of the crosslinking agent, e.g., vinyl or sulfhydryl. Theresulting SI-HPM has pendant silane structures which can react with thefiller to couple the SI-HPM resin to the filler and should have onlylimited reactivity with the elastomer during curing:

As an alternative option, hydrosilylation can be used to react with afunctional group of the HPM, e.g., a terminal vinyl group, to add areactive silane group, amine group, alkylamine group or the like:

In another embodiment, the HPM with olefinic unsaturation can bedynamically coupled to silica filler during the vulcanization of theelastomer with sulfur, for example. During curing the sulfur linkages insulfide-type silane coupling agents generally cleave to graft onto theolefinic unsaturation in the HPM (as well as the elastomer), therebycoupling the silica filler to the Si-HPM, in one or multiple crosslinks,depending on the degree of functionalization:

This cure system stabilizes the Si-HPM by coupling to the filler, andalso by co-curing with the elastomer where there is excess reactiveolefinic unsaturation in the Si-HPM, and further by increasing shearduring mixing of the elastomeric composition, thereby increasingviscosity of the system via the filler-coupled Si-HPM.

In an embodiment, the Si-HPM further comprises one or moreorganofunctional groups in addition to the silane functionality by whichthe Si-HPM can be crosslinked to itself, coupled to the filler or theelastomer, or otherwise anchored in the elastomeric matrix. These Si-HPMare capable of creating and participating in cross-linking within thecomposition medium by cross-linking with the other components of theadhesive formulation. In one example, residual olefinic unsaturation inthe Si-HPM can participate in the curing reaction, or can react with theorganofunctionality in a crosslinking or coupling agent, e.g., abifunctional organosilane coupling agent. In another example, anhydrideor acid groups in the Si-HPM can cross-link with themselves or withother polymers present in the composition medium.

As previously mentioned, the elastomeric composition can include, inaddition to the Si-HPM, a non-functionalized HPM or an HPMfunctionalized with a functional group(s) other than silane functionalgroups (FHPM), such as, for example, the grafted resins, graftedoligomers and/or blends thereof described in the aforementioned U.S.Pat. No. 7,294,664, incorporated by reference above. The Si-HPM/FHPM/HPMblends may be obtained by blending separate FHPM and/or HPM componentswith the Si-HPM, by partially functionalizing the HPM, and/or bypartially silane-functionalizing the FHPM or HPM.

Some polymers containing amine or alcoholic functionality will reactdirectly with the FHPM and/or Si-HPM, e.g., those polymers containingsome vinyl alcohol groups will react with carboxylic acid-functionalizedFHPM or Si-HPM. Other polymers will cross-link when a cross-linkingagent is added. In these embodiments, the amount of cross-linking agentadded is typically dependent on the amount of graft monomer present.Typical amounts include between 100:1 and 1:100, more preferably 1:1parts cross linking agent per parts graft monomer (molar ratio) presentin the formulation. These include polymers containing some acrylic acidsuch as ethylene alkyl-acrylate acrylic acid terpolymers or polymerscontaining succinic anhydride or acid groups such as maleic anhydridegrafted ethylene propylene diene rubbers. Such cross-linking can beachieved in many ways, including the addition of difunctional agentscapable of reacting with the acid or anhydride groups. Examples of suchmaterials are those containing alcohol and amine functionality such asdiols, diamines, especially primary amines. The material having thesefunctional groups may be mixed or have different substitutions, forexample a diamine where one group is primary and the other is tertiary.Weaker cross-linking can be achieved via interactions which do not formcovalent bonds such as ionic and hydrogen bonds. Examples of materialscapable of cross-linking in such a manner are divalent metal ions suchas Ca<++> or diamines containing quaternary amines. In an embodiment,crosslinking agents include alcohols, polyols, amines, diamines and/ortriamines Examples of organofunctional crosslinking agents in oneembodiment include polyamines such as ethylenediamine,diethylenetriamine, hexamethylenediamine, diethylaniinopropylamine,and/or menthanediamine.

Fillers and Additives

The elastomeric compositions produced in accordance with the presentinvention typically contain other components and additives customarilyused in rubber compounds, such as effective amounts of other processingaids, pigments, accelerators, cross-linking and curing materials,antioxidants, antiozonants, fillers, and/or clays. In addition to HPMthe elastomeric compositions may optionally include other usefulprocessing aids such as, for example, plastomers, polybutene, ormixtures thereof.

In addition to comprising at least one elastomer and at least onehydrocarbon polymer modifier, the elastomeric compositions may alsooptionally comprise at least one filler, for example, calcium carbonate,clay, mica, silica, silicates, talc, titanium dioxide, aluminum oxide,zinc oxide, starch, wood flour, carbon black, or mixtures thereof. Thefillers may be any size and typically range, for example, in the tireindustry, from about 0.0001 μm to about 100 μm.

As used herein, silica is meant to refer to any type or particle sizesilica or another silicic acid derivative, or silicic acid, processed bysolution, pyrogenic, or like methods, including untreated, precipitatedsilica, crystalline silica, colloidal silica, aluminum or calciumsilicates, fumed silica, and the like. Precipitated silica can beconventional silica, semi-highly dispersible silica, or highlydispersible silica.

The elastomeric composition may also include clay. The clay may be, forexample, montmorillonite, nontronite, beidellite, vokoskoite, laponite,hectorite, saponite, sauconite, magadite, kenyaite, stevensite,vermiculite, halloysite, aluminate oxides, hydrotalcite, or mixturesthereof, optionally, treated with modifying agents. The clay may containat least one silicate. Alternatively, the filler may be a layered clay,optionally, treated or pre-treated with a modifying agent such asorganic molecules; the layered clay may comprise at least one silicate.

The silicate may comprise at least one “smectite” or “smectite-typeclay” referring to the general class of clay minerals with expandingcrystal lattices. For example, this may include the dioctahedralsmectites which consist of montmorillonite, beidellite, and nontronite,and the trioctahedral smectites, which include saponite, hectorite, andsauconite. Also encompassed are synthetically prepared smectite-clays.

The silicate may comprise natural or synthetic phyllosilicates, such asmontmorillonite, nontronite, beidellite, bentonite, volkonskoite,laponite, hectorite, saponite, sauconite, magadite, kenyaite,stevensite, and the like, as well as vermiculite, halloysite, aluminumoxides, hydrotalcite, and the like. Micas such as kaolinite, sericite,phlogopite and muscovite may also be mentioned. Combinations of any ofthe above discussed silicates are also contemplated.

The layered filler such as the layered clays described above may bemodified such as intercalated or exfoliated by treatment with at leastone modifying agent. Modifying agents are also known as swelling orexfoliating agents. Generally, they are additives capable of undergoingion exchange reactions with the cations present at the interlayersurfaces of the layered filler. The modifying agent may be added as anadditive to the composition at any stage; for example, the additive maybe added to the elastomer, followed by addition of the layered filler,or may be added to a combination of at least one elastomer and at leastone layered filler; or the additive may be first blended with thelayered filler, followed by addition of the elastomer in yet anotherembodiment.

The filler may be carbon black or modified carbon black. The filler mayalso be a blend of carbon black and silica. In one embodiment, theelastomeric composition is a tire tread or sidewall and comprisesreinforcing grade carbon black at a level of from 10 to 100 phr of theblend, more preferably from 30 to 80 phr in another embodiment, and inyet another embodiment from 50 to 80 phr. Useful grades of carbon blackinclude the ranges of from N110 to N990.

Nanocomposites

Nanocomposites are filled polymer systems wherein the filler comprisesinorganic particles with at least one dimension in the nanometer range.Common types of inorganic particle used in nanocomposites arephyllosilicates, an inorganic substance from the general class of socalled “nanoclays” or “clays.” Due to general enhancement in air barrierqualities of various elastomeric compositions when a nanocomposite ispresent, there is a desire to have an elastomeric composition comprisinga nanocomposite comprising elastomer and clay. The hydrocarbon polymermodifiers in an embodiment can be used in nanocomposites to enhance gasbarrier properties. For example, the Si-HPM can improve dispersion ofthe nanoparticles in the elastomer, and the high molecular weight of theSi-HPM can help increase the length of the diffusion path of the gasmolecules, etc.

The inorganic particles (e.g., clays) can act as plate-like barriers tothe transmission of oxygen through the elastomeric composition. However,in order to be effective the inorganic particles need to be fullydispersed throughout the elastomeric composition. This can be difficult,as it generally requires the dispersion of polar clay in a generallynon-polar rubber. Ideally, intercalation should take place in thenanocomposite, wherein the polymer inserts into the space or gallerybetween the clay surfaces. Ultimately, it is desirable to have nearcomplete exfoliation, wherein the polymer is fully dispersed orintercalated with the individual nanometer-size clay platelets.

Suitable inorganic particles useful in nanocomposites can includeswellable inorganic clay materials, such as natural or syntheticphyllosilicates, particularly smectic clays such as montmorillonite,nontronite, beidellite, volkonskoite, laponite, hectorite, saponite,sauconite, magadite, kenyaite, stevensite and the like, as well asvermiculite, halloysite, aluminum oxides, hydrotalcite, and the like.These layered clays generally comprise particles containing a pluralityof silicate platelets having a thickness of 0.8-1.2 nm tightly boundtogether at an interlayer spacing of 0.4 nm or less, and containexchangeable cations such as Na⁺, Ca⁺², K⁺, or Mg⁺² present at theinterlayer surfaces.

In some embodiments, the clay can be mixed with an organic liquid toform a clay dispersion. The clay can be inorganic clay or an organicallymodified clay; the organic liquid can be miscible or immiscible inwater. In certain embodiments, the dispersion can have a clayconcentration in the range of 0.1 wt % to 5.0 wt %, or in the range of0.1 wt % to 3.0 wt %.

The layered clay may also be intercalated and exfoliated by treatmentwith organic molecules, typically known as swelling or exfoliatingagents or additives. The swelling/exfoliating agents are capable ofundergoing ion exchange reactions with the cations present at theinterlayer surfaces of the layered clay. For example, anintercalated/exfoliated clay may be produced through solution basedion-exchange reactions that replace sodium ions that exist on thesurface of the sodium montmorillonite clay with organic molecules(swelling/exfoliating agents), such as alkyl or aryl ammonium compounds.

Suitable exfoliating agents include cationic surfactants such asammonium ion, alkylamines or alkylammonium ion (primary, secondary,tertiary and quaternary), phosphonium or sulfonium derivatives ofaliphatic, aromatic or arylaliphatic amines, phosphines and sulfides.Desirable amine compounds (or the corresponding ammonium ion) are thosewith the structure R₁R₂R₃N, wherein R₁, R₂, and R₃ are C₁ to C₃₀ alkylsin one embodiment or C₂ to C₃₀ alkyls or alkenes in another embodiment,which may be the same or different. In one embodiment, the exfoliatingagent is a so called long chain tertiary amine, wherein at least R₁ is aC₁₄ to C₂₀ alkyl or alkene.

The exfoliating agent can also be a diamine compound (or thecorresponding ammonium or diammonium ion), such as diaminoalkane,N-alkyl-diaminoalkane, N,N-dialkyl-diaminoalkyl,N,N,N′-trialkyl-diaminoalkane, N,N,N′,N′-tetraalkyl-diaminoalkane, orthe like. Desirable diamines can have the structure R₄R₅N—R₆—NR₇R₈,wherein R₄, R₅, R₆, R₇, and R₈ are the same or different C₁ to C₃₀alkyls, or C₂ to C₃₀ alkyls or alkenes. When a long chain diamine isdesired, at least one of the N-alkyl or N-alkene groups has from 8 to 30carbon atoms, preferably from 14 to 20 carbon atoms. Specificnon-limiting, illustrative examples include N-coco-1,3-diaminopropane,N-oleyl-1,3-diaminopropane, N-tallow-1,3-diaminopropane, andN,N,N′-trimethyl-N′-tallow-1,3-diaminopropane.

Another class of exfoliating agents includes those which can becovalently bonded to the interlayer surfaces. These include polysilanesof the structure —Si(R₁₅)₂R₁₆ where R₁₅ is the same or different at eachoccurrence and is selected from alkyl, alkoxy or oxysilane and Rib is anorganic radical compatible with the matrix polymer of the composite.Other suitable exfoliating agents include protonated amino acids andsalts thereof containing 2-30 carbon atoms such as 12-aminododecanoicacid, epsilon-caprolactam and like materials. Suitable swelling agentsand processes for intercalating layered clay silicates are alsodisclosed in U.S. Pat. Nos. 4,472,538; 4,810,734; and 4,889,885, all ofwhich are incorporated herein by reference.

In a preferred embodiment, the exfoliating agent(s) are capable ofreaction with functional sites such as silyl groups, halogens, olefinicunsaturation or the like, on the interpolymer and/or elastomer to formcomplexes which help exfoliate the clay. In one embodiment, the agentincludes all primary, secondary, and tertiary amines and phosphines;alkyl and aryl sulfides and thiols; and their polyfunctional versions.Desirable agents include: long-chain tertiary amines such asN,N-dimethyl-octadecylamine, N,N-dioctadecyl-methylamine, so calleddihydrogenated tallowalkyl-methylamine and the like, andamine-terminated polytetrahydrofuran; long-chain thiol and thiosulfatecompounds like hexamethylene sodium thiosulfate.

In one embodiment, the exfoliating agent may be present in the range of0.1 to 20 phr or in the range of 0.2 to 15 phr, or in the range of 0.3to 10 phr in another embodiment. The exfoliating agent may be added tothe composition at any stage; for example, the agent may be added to theelastomer and/or interpolymer, followed by addition of the clay, or maybe added to the elastomer and/or interpolymer and clay mixture; or theadditive may be first blended with the clay, followed by blending withthe elastomer and/or interpolymer in yet another embodiment.

In another embodiment, improved impermeability is achieved by thepresence of at least one polyfunctional curative. An embodiment of suchpolyfunctional curatives can be described by the formula Z—R₁₇—Z′,wherein R₁₇ is one of a C₁ to C₁₅ alkyl, C₂ to C₁₅ alkenyl, and C₆ toC₁₂ cyclic aromatic moiety, substituted or unsubstituted; and Z and Z′are the same or different and are one of a thiosulfate group, mercaptogroup, aldehyde group, carboxylic acid group, peroxide group, alkenylgroup, or other similar group that is capable of crosslinking, eitherintermolecularly or intramolecularly, one or more strands of a polymer(elastomer and/or interpolymer) having reactive groups such asunsaturation. The polyfunctional curative, if present, may be present inthe composition in the range of 0.1 to 8 phr or in the range of 0.2 to 5phr in another embodiment.

The elastomeric composition may also include reversion resistors.Non-limiting examples of such reversion resistors includebis-thiosulfate compounds, such as hexamethylene bis(sodiumthiosulfate). Other reversion resistors are well known in the rubbercompounding arts, such as hexamethylene bis(cinnamaldehyde).

Treatment with the swelling agents results in intercalation or“exfoliation” of the layered clay platelets as a consequence of areduction of the ionic forces holding the layers of clay plateletstogether and introduction of molecules between layers which serve tospace the layers at distances of greater than 0.4 nm, preferably greaterthan 0.9 nm. This separation allows the layered clay silicate to morereadily absorb polymerizable monomer material and polymeric materialbetween the layers and facilitates further delamination of the layerswhen the intercalate is shear mixed with matrix polymer material toprovide a uniform dispersion of the exfoliated clay layers within thepolymer matrix.

The amount of clay or exfoliated clay incorporated in the elastomericcomposition is sufficient to develop an improvement in the mechanicalproperties or barrier properties of the composition by the formation ofa nanocomposite. Amounts of clay in the elastomeric compositiongenerally will be in the range of 0.5 wt % to 10 wt % or in the range of1 wt % to 8 wt %, or in the range of 1 wt % to 5 wt % in anotherembodiment, based on the polymer content of the composition. Expressedin parts per hundred parts of rubber, the clay or exfoliated clay may bepresent in the range of 1 to 30 phr or in the range of 2 to 20 phr.

Elastomer-clay nanocomposites can be formed using a variety of processesknown in the art, such as solution blending, melt blending, or anemulsion process. For example, U.S. Patent Application Publication2007/015853, incorporated herein by reference, discloses a method forpreparing clay-butyl rubber nanocomposites from an emulsion of rubbersolution and aqueous clay dispersion in which the clay can be aninorganic clay. As another example of nanocomposite processing, U.S.Pat. No. 7,501,460, incorporated herein by reference, discloses a methodfor preparing clay-butyl rubber nanocomposites by preparing aconcentrated nanocomposite from a slipstream of the rubber and blendingthe concentrate with a main rubber stream.

In one embodiment, the elastomeric composition may contain ananocomposite formed by a polymer melt blending process. For example,the elastomer and clay components may be blended to form an intercalatein any suitable mixing device such as a BANBURY mixer, BRABENDER mixer,or preferably a mixer/extruder and mixing at temperatures in the rangeof 120° C. up to 300° C., under conditions of shear sufficient to allowthe clay to intercalate and to exfoliate and become uniformly dispersedwithin the polymer to form the nanocomposite.

In another embodiment, a nanocomposite may be formed by an emulsionprocess. For example, the emulsions may be formed by conventionalemulsion technology, that is, subjecting a mixture of the hydrocarbon,water, and surfactant, when used, to sufficient shearing, as in acommercial blender or its equivalent for a period of time sufficient forforming the emulsion, e.g., generally at least a few seconds. Theemulsion can be allowed to remain in emulsion form, with or withoutcontinuous or intermittent mixing or agitation, with or without heatingor other temperature control, for a period sufficient to enhanceexfoliation of the clay, for example, from 0.1 to 100 hours or more inone embodiment, or from 1 to 50 hours, or from 2 to 20 hours in anotherembodiment.

Useful cationic surfactants include tertiary amines, diamines,polyamines, amine salts, as well as quaternary ammonium compounds.Useful non-ionic surfactants include alkyl ethoxylates, linear alcoholethoxylates, alkyl glucosides, amide ethoxylates, amine ethoxylates(coco-, tallow-, and oleyl-amine ethoxylates for example), phenolethoxylates, and nonyl phenol ethoxylates. The surfactant concentrationis generally that which will allow the formation of a relatively stableemulsion; in preferred embodiments, the amount of surfactant employed isat least 0.001 wt % of the total emulsion, more preferably in the rangeof 0.001 wt % to about 3 wt %, and most preferably in the range of 0.01wt % to 2 wt %.

In other embodiments, the nanocomposite may be formed by solutionblending. For example, the nanocomposite may be produced by contactingSolution A comprising a solvent comprising a hydrocarbon and at leastone layered filler or clay with Solution B comprising a solvent and atleast one elastomer, and removing the solvents from the contact productof Solution A and Solution B to form a nanocomposite. The layered claymay be treated with a swelling/exfoliating agent. In yet anotherembodiment, a nanocomposite is produced by a process comprisingcontacting at least one elastomer and at least one layered filler in atleast one or more solvents; and removing the solvent(s) from the productto form a nanocomposite. In yet another embodiment, a nanocomposite isproduced by a process to form a contact product comprising dispersing atleast one layered filler and then dissolving at least one elastomer in asolvent or solvent mixture comprising at least two solvents; andremoving the solvent mixture from the contact product to form ananocomposite.

In solution blending processes, the solvents may be present in the rangeof 30 wt % to 99 wt %, alternatively 40 wt % to 99 wt %, alternatively60 wt % to 99 wt %, alternatively 80 wt % to 99 wt %, alternatively inthe range of 90 wt % to 99 wt %, alternatively from 95 wt % to 99 wt %,based upon the total weight of the composition.

Crosslinking Agents, Curatives, Cure Packages, and Curing

The elastomeric compositions and the articles made from thosecompositions are generally manufactured with the aid of at least onecure package, at least one curative, at least one crosslinking agent,and/or undergo a process to cure the elastomeric composition. As usedherein, cure package refers to any material or method capable ofimparting cured properties to a rubber as is commonly understood in theindustry.

One or more crosslinking agents are generally used in the elastomericcompositions of the present invention, especially when silica is theprimary filler, or is present in combination with another filler.Crosslinking and curing agents include sulfur, zinc oxide, and fattyacids. More preferably, the curing agent may be a bifunctionalorganosilane crosslinking agent. An “organosilane crosslinking agent” isany silane coupled filler and/or crosslinking activator and/or silanereinforcing agent known to those skilled in the art including, but notlimited to, vinyl triethoxysilane,vinyl-tris-(beta-methoxyethoxy)silane,methacryloylpropyltrimethoxysilane, gamma-amino-propyl triethoxysilane(sold commercially as A1100 by Witco),gamma-mercaptopropyltrimethoxysilane (A189 by Witco) and the like, andmixtures thereof. In one embodiment,bis-(3-triethoxysilypropyl)tetrasulfide (sold commercially as “Si69”) isemployed.

Generally, polymer blends are crosslinked to improve the mechanicalproperties of the polymer. Physical properties, performancecharacteristics, and durability of vulcanized rubber compounds are knownto be related to the number (crosslink density) and type of crosslinksformed during the vulcanization reaction. Polymer blends may becrosslinked by adding curative agents, for example sulfur, metals, metaloxides such as zinc oxide, peroxides, organometallic compounds, radicalinitiators, fatty acids, and other agents common in the art. Other knownmethods of curing that may be used include, peroxide cure systems, resincure systems, and heat or radiation-induced crosslinking of polymers.Accelerators, activators, and retarders may also be used in the curingprocess.

The compositions may be vulcanized (cured) by any suitable means, suchas subjecting them to heat or radiation according to any conventionalvulcanization process. The amount of heat or radiation needed is thatwhich is required to affect a cure in the composition, and the inventionis not herein limited by the method and amount of heat required to curethe composition. Typically, the vulcanization is conducted at atemperature ranging from about 100° C. to about 250° C. in oneembodiment, from 150° C. to 200° C. in another embodiment, for about 1to 150 minutes.

Halogen-containing elastomers may be crosslinked by their reaction withmetal oxides. Examples of useful metal oxides include, but are notlimited to, ZnO, CaO, and PbO. The metal oxide can be used alone or inconjunction with its corresponding metal fatty acid complex (e.g., zincstearate, calcium stearate, etc.), or with the organic and fatty acidsadded alone, such as stearic acid, and optionally other curatives suchas sulfur or a sulfur compound, an alkylperoxide compound, diamines orderivatives thereof.

Sulfur is the most common chemical vulcanizing agent fordiene-containing elastomers. The sulfur vulcanization system may consistof an activator to activate the sulfur, an accelerator, and a retarderto help control the rate of vulcanization.

Activators are chemicals that increase the rate of vulcanization byreacting first with the accelerators to form rubber-soluble complexeswhich then react with the sulfur to form sulfurating agents. Generalclasses of accelerators include amines, diamines, guanidines, thioureas,thiazoles, thiurams, sulfenamides, sulfenimides, thiocarbamates,xanthates, and the like.

Accelerators help control the onset of and rate of vulcanization, andthe number and type of crosslinks that are formed. Retarders may be usedto delay the initial onset of cure in order to allow sufficient time toprocess the unvulcanized rubber.

The acceleration of the vulcanization process may be controlled byregulating the amount of the acceleration accelerant, often an organiccompound. The mechanism for accelerated vulcanization of natural rubber,BR, and SBR involves complex interactions between the curative,accelerator, activators, and polymers. Ideally, the entire availablecurative is consumed in the formation of effective crosslinks which jointogether two polymer chains and enhance the overall strength of thepolymer matrix. Numerous accelerators are known in the art and include,but are not limited to, the following: stearic acid, diphenyl guanidine(DPG), tetramethylthiuram disulfide (TMTD), benzothiazyl disulfide(MBTS), N-t-butyl-2-benzothiazole sulfenamide (TBBS),N-cyclohexyl-2-benzothiazole-sulfenamide (CBS), and thioureas.

In one embodiment of the invention, at least one curing agent(s) ispresent from 0.2 to 10 phr, or from 0.5 to 5 phr, or in anotherembodiment from 0.75 phr to 2 phr.

Processing

The inventive elastomeric composition may be compounded (mixed) by anyconventional means known to those skilled in the art. The mixing mayoccur in a single step or in multiple stages. For example, theingredients are typically mixed in at least two stages, namely at leastone non-productive stage followed by a productive mixing stage. Thefinal curatives are typically mixed in the final stage which isconventionally called the “productive” mix stage. In the productive mixstage the mixing typically occurs at a temperature, or ultimatetemperature, lower than the mix temperature(s) of the precedingnon-productive mix stage(s). The elastomers, polymer additives, silicaand silica coupler, and carbon black, if used, are generally mixed inone or more non-productive mix stages. The terms “non-productive” and“productive” mix stages are well known to those having skill in therubber mixing art.

In one embodiment, the filler is added in a different stage from zincoxide and other cure activators and accelerators. In another embodiment,antioxidants, antiozonants, and processing materials are added in astage after the carbon black has been processed with the elastomers, andzinc oxide is added at a final stage to maximize the compound modulus.In a further embodiment, mixing with the clays is performed bytechniques known to those skilled in the art, wherein the clay is addedto the polymer at the same time as the filler. In other embodiments,additional stages may involve incremental additions of one or morefillers.

In another embodiment, mixing of the components may be carried out bycombining the elastomer components, filler and clay in any suitablemixing device such as a two-roll open mill, BRABENDER™ internal mixer,BANBURY™ internal mixer with tangential rotors, Krupp internal mixerwith intermeshing rotors, or preferably a mixer/extruder, by techniquesknown in the art. Mixing may be performed at temperatures up to themelting point of the elastomer(s) used in the composition in oneembodiment, or from 40° C. to 250° C. in another embodiment, or from100° C. to 200° C. in yet another embodiment. Mixing should generally beconducted under conditions of shear sufficient to allow the clay toexfoliate and become uniformly dispersed within the elastomer(s).

Typically, from 70% to 100% of the elastomer or elastomers is firstmixed for 20 to 90 seconds, or until the temperature reaches from 40° C.to 75° C. Then, approximately 75% of the filler, and the remainingamount of elastomer, if any, are typically added to the mixer, andmixing continues until the temperature reaches from 90° C. to 150° C.Next, the remaining filler is added, as well as the processing aids, andmixing continues until the temperature reaches from 140° C. to 190° C.The masterbatch mixture is then finished by sheeting on an open mill andallowed to cool, for example, to from 60° C. to 100° C. when curativesmay be added.

INDUSTRIAL APPLICABILITY

The elastomeric compositions of the invention may be extruded,compression molded, blow molded, injection molded, and laminated intovarious shaped articles including fibers, films, laminates, layers,industrial parts such as automotive parts, appliance housings, consumerproducts, packaging, and the like.

In particular, the elastomeric compositions are useful in components fora variety of tire applications such as truck tires, bus tires,automobile tires, motorcycle tires, off-road tires, aircraft tires, andthe like. Such tires can be built, shaped, molded, and cured by variousmethods which are known and will be readily apparent to those havingskill in the art. The elastomeric compositions may either be fabricatedinto a finished article or a component of a finished article such as aninnerliner for a tire. The component may be selected any tire componentsuch as air barriers, air membranes, films, layers (microlayers and/ormultilayers), innerliners, inner tubes, air sleeves, sidewalls, treads,tire curing bladders, and the like. The elastomeric composition may beparticularly useful in a tire tread.

The elastomeric compositions of the present invention are useful in avariety of applications, particularly pneumatic tire components, hoses,belts such as conveyor belts or automotive belts, solid tires, footwearcomponents, rollers for graphic arts applications, vibration isolationdevices, pharmaceutical devices, adhesives, caulks, sealants, glazingcompounds, protective coatings, air cushions, pneumatic springs, airbellows, accumulator bags, and various bladders for fluid retention andcuring processes. They are also useful as plasticizers in rubberformulations; as components to compositions that are manufactured intostretch-wrap films; as dispersants for lubricants; and in potting andelectrical cable filling and cable housing materials.

The elastomeric compositions may also be useful in molded rubber partsand may find wide applications in automobile suspension bumpers, autoexhaust hangers, and body mounts. In yet other applications, theelastomer(s) or elastomeric compositions of the invention are alsouseful in medical applications such as pharmaceutical stoppers andclosures and coatings for medical devices.

The invention has been described above with reference to numerousembodiments and specific examples. Many variations will suggestthemselves to those skilled in this art in light of the above detaileddescription. All such obvious variations are within the full intendedscope of the appended claims.

We claim:
 1. An elastomeric composition comprising (i) at least oneelastomer; (ii) at least one filler; (iii) at least onesilane-functionalized hydrocarbon polymer modifier (Si-HPM) made in apre-reaction wherein the Si-HPM comprises an interpolymer comprising atleast one monomer chosen from piperylenes, cyclic pentadienes,aromatics, limonenes, pinenes, and amylenes; and (iv) at least onefunctional group comprising a silane structure.
 2. The elastomericcomposition of claim 1, wherein the one or more functional groupsfurther comprise olefinic unsaturation, wherein the interpolymercomprises at least 1 mole percent olefinic hydrogen, based on the totalmoles of hydrogen in the interpolymer.
 3. The elastomeric composition ofclaim 1, wherein the Si-HPM comprises the reaction product of theinterpolymer and a bifunctional organosilane crosslinking agent of theformula:X₃Si—R—F—[R—Si—X₃]_(p) wherein each X is independently a siliconfunctional group, each R is independently a divalent substituted orunsubstituted hydrocarbon group of from 1 to 20 carbon atoms, F is amonovalent or multivalent organo-functional group, p is 0 when F ismonovalent and p is at least 1 when F is multivalent.
 4. The elastomericcomposition of claim 3, wherein X is hydroxy or R¹—O— wherein R¹ is analkyl, alkoxyalkyl, aryl, aralkyl or cycloalkyl group of up to 20 carbonatoms, R is alkylene, wherein p is 0 or 1, and when p is 0 F is selectedfrom amino, amido, hydroxy, alkoxy, halo, mercapto, hydrosilyl, carboxy,acyl, vinyl, allyl, styryl, ureido, epoxy, isocyanato, glycidoxy, andacryloxy groups, and when p is 1 F is divalent polysulfide of from 2 to20 sulfur atoms.
 5. The elastomeric composition of claim 1, wherein theat least one filler comprises silica.
 6. The elastomeric composition ofclaim 1, wherein the interpolymer comprises (i) at least one piperylenecomponent; (ii) at least one cyclic pentadiene component; and (iii) atleast one aromatic component, wherein the interpolymer comprises asoftening point from 40° C. to 160° C.
 7. The elastomeric composition ofclaim 1, wherein the interpolymer is coupled via at least one of the oneor more functional groups to the at least one elastomer.
 8. Theelastomeric composition of claim 1, wherein the interpolymer is coupledvia at least one of the one or more functional groups to the at leastone filler.
 9. The elastomeric composition of claim 1, wherein theinterpolymer is coupled to a combination of the at least one elastomerand the at least one filler.
 10. The elastomeric composition of claim 1,wherein the at least one elastomer is coupled to the at least onefiller.
 11. The elastomeric composition of claim 1, wherein theinterpolymer is immiscible with the at least one elastomer.
 12. Theelastomeric composition of claim 1, wherein the Si-HPM has a glasstransition temperature of from about 60° C. to 100° C.
 13. Theelastomeric composition of claim 1 comprising about 100 phr of the atleast one elastomer, from about 50 to about 90 phr of the at least onefiller, and from about 5 to about 50 phr of the at least one Si-HPM. 14.A tire or tire component comprising the elastomeric composition ofclaim
 1. 15. A method of forming an article, comprising: (a) forming asilane-functionalized hydrocarbon polymer modifier (Si-HPM) bypre-reacting (i) at least one hydrocarbon polymer modifier wherein thehydrocarbon polymer modifier comprises an interpolymer comprising atleast one functional group and at least one monomer chosen frompiperylenes, cyclic pentadienes, aromatics, limonenes, pinenes, andamylenes with (ii) an organosilane crosslinking agent (b) meltprocessing an elastomeric mixture to form an elastomeric composition inthe shape of an article, wherein the elastomeric mixture comprises (i)at least one elastomer; (ii) the silane-functionalized hydrocarbonpolymer modifier; and (iii) a filler comprising silica; and (c) curingthe elastomeric composition to form the article.
 16. The method of claim15, comprising coupling the Si-HPM to one or both of the elastomer andthe filler, coupling the elastomer to one or both of the Si-HPM and thefiller, and coupling the filler to one or both of the Si-HPM and theelastomer.
 17. The method of claim 15, wherein the organosilanecrosslinking agent is a silane having the formula:X₃Si—R—F—[R—Si—X₃]_(p) wherein each X is independently a siliconfunctional group, each R is independently a divalent hydrocarbon groupof from 1 to 20 carbon atoms, F is a monovalent or bivalentorgano-functional group, p is 0 when F is monovalent and p is 1 when Fis divalent.
 18. The method of claim 15, wherein the organosilanecrosslinking agent is bifunctional.
 19. The method of claim 15, whereinthe Si-HPM comprises at least 1 mol % olefinic hydrogen, based on thetotal moles of hydrogen in the Si-HPM.
 20. The method of claim 15,further comprising adhering a build component to a surface of theelastomeric composition and co-curing the build component with thearticle to form a construct.
 21. The method of claim 19, wherein theconstruct comprises a tire and the article comprises a tire tread, atire innerliner or a tire carcass.